1. Field of the Invention
The present invention relates to an image processing apparatus and an image processing method for performing further image processing on an image data set which was obtained with a photography device such as a digital camera, having a function of performing image processing on an image data set. The further image processing is performed on the image data set on which image processing has already been performed and to which image processing information about the performed image processing has been attached. The present invention also relates to a program for causing a computer to execute the image processing method.
2. Description of the Related Art
In digital cameras, images obtained by photography may be recorded as digital image data sets in recording media, such as internal memories in the digital cameras, and IC cards. The images obtained by photography may be reproduced by printers or monitors based on the recorded digital image data sets. When the images obtained with the digital cameras are reproduced, there is expectation that high quality images similar to prints reproduced from negative films will be reproduced.
When prints are obtained from the digital image data sets as described above, the image quality of the prints may be improved by performing various kinds of image processing on the image data sets, such as exposure correction processing, white balance adjustment processing, gradation correction processing, color correction processing and sharpness processing. A method for obtaining prints having higher image quality has been proposed, wherein image data sets which were obtained with digital cameras and to which photography information such as with/without flash and a type of lighting has been attached are output, and wherein when image processing is performed, the image processing is performed on the image data sets in a more appropriate manner with reference to the photography information attached to the image data sets (U.S. Pat. No. 6,011,547).
Meanwhile, digital cameras have also been proposed, which can output processed image data sets by automatically or manually performing image processing on image data sets obtained by photography. In such digital cameras having image processing functions, image processing is performed on the image data sets so that optimum image quality is attained according to photographed scenes and photography conditions. Further, photographers may intentionally select kinds of image processing which will be performed on the image data sets and various kinds of functions related to the image processing by setting image processing modes. For example, the kinds of image processing such as automatic white balance adjustment processing, white balance adjustment processing in a fixed light source type mode (a tungsten mode, a cloudy sky mode, a shade mode or the like), image quality modification processing (gradation, sharpness and saturation), taste in reproduction images (monochrome, sepia, beautiful skin or the like) and finish setting modes (a night view/fireworks mode, a portrait mode, a landscape/distant view mode, a macro/close-up mode, an underwater photography mode, a user exposure correction mode or the like) maybe selected. Further, the various kinds of functions related to image processing, such as an automatic bracket function, photography using an optical filter, soft-focus photography, interval photography, continuous shooting, multiple exposure, synthesis with a template and synthesis with a frame may be selected. Accordingly, optimum image processing may be performed according to the image processing mode so that photographers' intentions may be reflected in the image processing. If the shade mode has been set as the fixed light source type mode, image processing is performed on an image data set obtained by photography so that an RGB gain of the image data set is adjusted toward a YR (namely, orange) direction.
When image data sets obtained with digital cameras having image processing functions as described above are reproduced on printers or monitors, further image processing is performed on the image data sets. However, if the further image processing is performed on the image data sets on which image processing has already been performed, reproduced images might not have the image quality intended for at the digital cameras or at the reproduction devices. Therefore, a method has been proposed, wherein image processing is performed on image data sets based on image processing information indicating image processing modes, attached to the image data sets, in considering image processing related to the image processing information, which has already been performed on the image data sets (U.S. patent Laid-Open No. 20030197879). In this method, image processing which has already been performed on the image data sets is considered. Therefore, processed image data sets on which image processing has been performed in an appropriate manner may be obtained.
However, if a user of a digital camera erroneously sets a photography mode, although image processing which was not intended by the user has been performed on the image data set, image processing is performed taking the image processing, which was not intended by the user, into consideration. Therefore, an image having image quality intended by the user may not be reproduced.
For example, if a photograph is taken in outdoor light by setting a tungsten mode, an image represented by an obtained image data set will have a cyan or bluish cast. If a photograph is taken in tungsten light by setting a cloudy sky mode or a shade mode, an image represented by an obtained image data set will have an orange cast. In photography devices of some manufacturers, when a portrait mode is set, a photograph is taken with a shallow depth-of-field by opening an aperture. Further, image processing is performed on the obtained image data set to reduce sharpness and soften gradation. Meanwhile, when a landscape mode is set, a photograph is taken with a deep depth-of-field by closing an aperture. Further, image processing is performed on the obtained image data set to increase sharpness and harden gradation. Therefore, if a landscape is photographed while the device is set in the portrait mode, an image represented by an obtained image data set becomes unsharp. If a person is photographed while the device is set in the landscape mode, sharpness is emphasized too much in an image represented by an obtained image data set and flesh colors become rough.